[eyedigress]

That map says quite a bit. The Great Lakes manufacturing had to drain to New Orleans. They new what was coming.

[x]

Notice the rapid expansion of East-West lines in the North.

Consider also the longer sailing times from New Orleans to Europe versus New York to Europe.

Also, look at the population map. You'd have more customers in the East accessible by rail, than in the South or Europe.

Thanks to cotton, New Orleans had been a major US export port for decades, but the much lower level of imports was likely a sign of structural conditions that would take more than a difference in tariffs to remedy.

Urban Colossus: Why Is New York America's Largest City?